scholarly journals Coyote diet patterns in the Mojave Desert: implications for threatened desert tortoises

2018 ◽  
Vol 24 (1) ◽  
pp. 44 ◽  
Author(s):  
Brian L. Cypher ◽  
Erica C. Kelly ◽  
Tory L. Westall ◽  
Christine L. Van Horn Job
Keyword(s):  
Mojave Desert ◽  
Dietary Diversity ◽  
Generalist Predators ◽  
Gopherus Agassizii ◽  
Low Frequencies ◽  
Diet Patterns ◽  
Food Items ◽  
High Predation ◽  
Anthropogenic Food ◽  
Predation Rates

Coyotes (Canis latrans) are generalist predators and are ubiquitous in North America. Occasionally, predation by coyotes can pose a threat to populations of rare species. We assessed diet patterns of coyotes over a 5-year period (2009–14) in a region of the Mojave Desert where high predation rates on threatened desert tortoises (Gopherus agassizii) had been reported. Our goal was to identify primary food items for coyotes and to assess the importance of desert tortoises in the diet. Coyotes primarily consumed rabbits and rodents with rabbits being consumed preferentially and rodents, along with secondary foods including various birds, reptiles, arthropods, and fruits, being consumed more opportunistically. In response to low annual precipitation in the last three years of the study, dietary diversity increased, as did use of anthropogenic food items by coyotes. However, coyotes did not seem to be dependent upon anthropogenic items. Remains of desert tortoises occurred in coyote scats at low frequencies (<6%) in all years and seasons, and use of tortoises appeared to be opportunistic as use varied with tortoise abundance. In the portion of the study area where 571 translocated desert tortoises had been released in 2008, the frequencies of tortoise remains in coyote scats were markedly higher in the two years following the releases (7.5% and 8.8%, respectively). The high predation rates on tortoises reported in this area may have resulted from focussed coyote foraging efforts due to the availability of vulnerable individuals (e.g. disoriented and displaced tortoises) as well as higher tortoise densities.

Exploitative competition between desert kit foxes and coyotes in the Mojave Desert

2020 ◽  
Vol 26 (1) ◽  
pp. 57
Author(s):  
Erica C. Kelly ◽  
Brian L. Cypher ◽  
David J. Germano
Keyword(s):  
Mojave Desert ◽  
Food Habits ◽  
Dietary Diversity ◽  
Conservation Strategies ◽  
Natural Food ◽  
Exploitative Competition ◽  
Ecological Community ◽  
Food Items ◽  
Heteromyid Rodents ◽  
Abundance And Diversity

Exploitative competition between two sympatric guild members can influence the composition and dynamics of an ecological community. We assessed potential exploitative competition between desert kit foxes (Vulpes macrotis arsipus) and coyotes (Canis latrans) by comparing food habits of the two species from 2009 to 2014 on a study site in the Mojave Desert in California. Desert kit foxes specialised on heteromyid rodents and invertebrates, while the most frequently occurring items consumed by coyotes were lagomorphs and rodents. Both species consumed a variety of food items throughout the study, but relative use of these items varied with year and season. Also, precipitation affected prey abundance, and this influenced prey consumption by the two species. The diets of desert kit foxes and coyotes overlapped extensively, which indicated possible exploitative competition. Desert kit foxes consistently had lower dietary diversity than coyotes, indicating that desert kit foxes are more specialist consumers while coyotes are more generalists. Dietary specialisation by kit foxes on smaller items may help reduce competition with coyotes and facilitate coexistence. Coyotes consumed anthropogenic material at much higher frequencies than desert kit foxes, and this subsidisation could increase competitive pressures on kit foxes if it results in greater coyote abundance. Desert kit foxes in California are not a protected species although formal protection has been proposed due to increasing human encroachment. Conservation strategies should include measures to maintain an abundance and diversity of natural food items and limit anthropogenic subsidisation of coyotes.

Effects of Predation and Trophic Conditions on the Reproduction of Tylototriton verrucosus (Caudata: Salamandridae) in Darjeeling

2011 ◽  
Vol 4 (2) ◽  
pp. 163-169 ◽  
Author(s):  
Ritwik Dasgupta
Keyword(s):  
Frequency Distribution ◽  
Primary Productivity ◽  
Egg Size ◽  
Zooplankton Abundance ◽  
Trophic Conditions ◽  
Size Frequency Distribution ◽  
Size Frequency ◽  
High Predation ◽  
Hatchling Size ◽  
Predation Rates

The facts that small hatchlings emerged from small eggs laid under high predation levels prevailing at the lower altitudes of distribution of this species in Darjeeling while larger hatchlings emerged from larger eggs laid under lower levels of predation at higher altitudes, show that predation is not selected for large egg and initial hatchling size in this salamandrid species. Metamorphic size was small under high predation rates because this species relied on crypsis for evading predators. Egg and hatchling size are related inversely to levels of primary productivity and zooplankton abundance in lentic habitats. Hatchling sizes are related positively to egg size and size frequency distribution of zooplankton. Small egg and small hatchling size have been selected for at the lower altitudes of distribution of this salamandrid in Darjeeling because predation rates increased in step with improvement in trophic conditions at the lower altitudes.

scholarly journals Do Repugnant Scents Increase Survival of Ground Nests? A Test with Artificial and Natural Duck Nests

2007 ◽  
Vol 121 (2) ◽  
pp. 150
Author(s):  
Vanessa B. Harriman ◽  
Justin A. Pitt ◽  
Serge Larivière
Keyword(s):  
Human Hair ◽  
Nest Predation ◽  
Survival Rates ◽  
Olfactory Cues ◽  
Artificial Nests ◽  
Treatment Groups ◽  
Mammalian Predators ◽  
High Predation ◽  
Ground Nesting ◽  
Predation Rates

Ground-nesting birds typically experience high predation rates on their nests, often by mammalian predators. As such, researchers and wildlife managers have employed numerous techniques to mitigate nest predation. We investigated the use of scents as repellents to deter predators from both artificial and natural ground nests. Survival rates of artificial nests did not differ among six groups of substances (Wald ?2 df = 5 = 4.53, P < 0.48); however the chronology of predation among groups differed. A commercial Coyote urine based deterrent (DEER-D-TERTM), human hair, and Worcestershire sauce were depredated faster than the control (F4,5 = 40.3, P < 0.001). Nest survival of natural nests differed among those groups tested (Wald ?2 df = 2 = 11.8, P < 0.005); the eight mothball treatment decreased survival (Wald ?2 df = 1 = 11.5, P < 0.005), which indicated that novel smells may attract predators or result in duck nest abandonment when coupled with natural duck scent. Chronologies of predation events among treatment groups were not different for natural nests (F2,3 = 1.9, P = 0.22). These findings indicate an interaction between novel scents and predator olfactory cues.

Seasonal Reproductive Cycle of the Desert Tortoise (Gopherus agassizii) in the Eastern Mojave Desert

1994 ◽  
Vol 8 ◽  
pp. 72 ◽  
Author(s):  
David C. Rostal ◽  
Valentine A. Lance ◽  
Janice S. Grumbles ◽  
Allison C. Alberts
Keyword(s):  
Reproductive Cycle ◽  
Mojave Desert ◽  
Gopherus Agassizii ◽  
Desert Tortoise

scholarly journals Effects of Temporal Crop β Diversification of a Cereal-Based Cropping System on Generalist Predators and Their Biocontrol Potential

2021 ◽  
Vol 3 ◽  
Author(s):  
Giovanni Antonio Puliga ◽  
Jan Thiele ◽  
Hauke Ahnemann ◽  
Jens Dauber
Keyword(s):  
Crop Rotation ◽  
Pest Control ◽  
Cover Crops ◽  
Cropping Systems ◽  
Cropping System ◽  
Generalist Predators ◽  
Activity Density ◽  
Biocontrol Potential ◽  
Natural Pest Control ◽  
Predation Rates

In agroecosystems, crop diversification plays a fundamental role in maintaining and regenerating biodiversity and ecosystem services, such as natural pest control. Temporal diversification of cropping systems can affect the presence and activity of natural enemies by providing alternative hosts and prey, food, and refuges for overwintering. However, we still lack studies on the effects of temporal diversification on generalist predators and their biocontrol potential conducted at field scale in commercial agricultural settings. Here, we measured proxies of ecosystem functions related with biological pest control in 29 commercial agricultural fields characterized by cereal-based cropping system in Lower-Saxony, northern Germany. The fields differed in the number of crops and cover crops cultivated during the previous 12 years. Using the Rapid Ecosystem Function Assessment approach, we measured invertebrate predation, seed predation and activity density of generalist predators. We aimed at testing whether the differences in the crop rotations from the previous years would affect activity of predators and their predation rates in the current growing season. We found that the length of the crop rotation had neutral effects on the proxies measured. Furthermore, predation rates were generally lower if the rotation comprised a higher number of cover crops compared to rotation with less cover crops. The activity density of respective taxa of predatory arthropods responded differently to the number of cover crops in the crop rotation. Our results suggest that temporal crop diversity may not benefit the activity and efficiency of generalist predators when diversification strategies involve crops of very similar functional traits. Adding different resources and traits to the agroecosystems through a wider range of cultivated crops and the integration of semi-natural habitats are aspects that need to be considered when developing more diverse cropping systems aiming to provide a more efficient natural pest control.

scholarly journals Improved draft of the Mojave Desert tortoise genome, Gopherus agassizii, version 1.1

2017 ◽  
Author(s):  
Timothy H Webster ◽  
Greer A. Dolby ◽  
Melissa Wilson Sayres ◽  
Kenro Kusumi
Keyword(s):  
Threatened Species ◽  
Mojave Desert ◽  
Gene Annotation ◽  
Draft Genome ◽  
Gopherus Agassizii ◽  
Desert Tortoise ◽  
Draft Genome Assembly ◽  
Initial Release ◽  
Exogenous Sequence ◽  
Mojave Desert Tortoise

Exogenous sequence contamination presents a challenge in first-draft genomes because it can lead to non-contiguous, chimeric assembled sequences. This can mislead downstream analyses reliant on synteny, such as linkage-based analyses. Recently, the Mojave Desert Tortoise (Gopherus agassizii) draft genome was published as a resource to advance conservation efforts for the threatened species and discover more about chelonian biology and evolution. Here, we illustrate steps taken to improve the desert tortoise draft genome by removing contaminating sequences—actions that are typically carried out after the initial release of a draft genome assembly. We used information from NCBI’s Vecscreen output to remove intra-scaffold contamination and trim heading and trailing Ns. We then reordered and renamed scaffolds, and transferred the gene annotation onto this assembly. Finally, we describe the tools developed for this pipeline, freely available on Github (https://github.com/thw17/G_agassizii_reference_update), which facilitate post-assembly processing of other draft genomes. The new gopAga1.1 genome has an N50 of 251 KB, L50 of 2592 scaffolds, and its annotation retains 17,201 of the original 20,172 genes that were unaffected by the scaffold processing.

scholarly journals Improved draft of the Mojave Desert tortoise genome, Gopherus agassizii, version 1.1

2018 ◽  
Author(s):  
Timothy H Webster ◽  
Greer A Dolby ◽  
Melissa A Wilson Sayres ◽  
Kenro Kusumi
Keyword(s):  
Threatened Species ◽  
Mojave Desert ◽  
Gene Annotation ◽  
Draft Genome ◽  
Gopherus Agassizii ◽  
Desert Tortoise ◽  
Draft Genome Assembly ◽  
Initial Release ◽  
Exogenous Sequence ◽  
Mojave Desert Tortoise

Exogenous sequence contamination presents a challenge in first-draft genomes because it can lead to non-contiguous, chimeric assembled sequences. This can mislead downstream analyses reliant on synteny, such as linkage-based analyses. Recently, the Mojave Desert Tortoise (Gopherus agassizii) draft genome was published as a resource to advance conservation efforts for the threatened species and discover more about chelonian biology and evolution. Here, we illustrate steps taken to improve the desert tortoise draft genome by removing contaminating sequences—actions that are typically carried out after the initial release of a draft genome assembly. We used information from NCBI’s Vecscreen output to remove intra-scaffold contamination and trim heading and trailing Ns. We then reordered and renamed scaffolds, and transferred the gene annotation onto this assembly. Finally, we describe the tools developed for this pipeline, freely available on Github (https://github.com/thw17/G_agassizii_reference_update), which facilitate post-assembly processing of other draft genomes. The new gopAga1.1 genome has an N50 of 251 kb, L50 of 2592 scaffolds, and its annotation retains 17,201 of the original 20,172 genes that were unaffected by the scaffold processing.

scholarly journals Investigating differences in dietary patterns among a small cross-sectional study of young and old Pacific peoples in NZ using exploratory factor analysis: a feasibility study

BMJ Open ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. e023126 ◽  
Author(s):  
Ridvan Tupai-Firestone ◽  
Soo Cheng ◽  
Joseph Kaholokula ◽  
Barry Borman ◽  
Lis Ellison-Loschmann
Keyword(s):  
New Zealand ◽  
Dietary Patterns ◽  
Generational Differences ◽  
Dietary Diversity ◽  
Limited Range ◽  
Healthy Diet ◽  
Food Groups ◽  
Cross Sectional ◽  
Food Items ◽  
The Relationship

ObjectivesObesity among Pasifika people living in New Zealand is a serious health problem with prevalence rates more than twice those of the general population (67% vs 33%, respectively). Due to the high risk of developing obesity for this population, we investigated diet quality of Pacific youth and their parents and grandparents. Therefore, we examined the dietary diversity of 30 youth and their parents and grandparents (n=34) to identify whether there are generational differences in dietary patterns and investigate the relationship between acculturation and dietary patterns.MethodsThe study design of the overarching study was cross-sectional. Face-to-face interviews were conducted with Pasifika youth, parents and grandparents to investigate dietary diversity, that included both nutritious and discretionary food items and food groups over a 7 day period. Study setting was located in 2 large urban cities, New Zealand. Exploratory factor analyses were used to calculate food scores (means) from individual food items based on proportions consumed over the week, and weights were applied to calculate a standardised food score. The relationship between the level of acculturation and deprivation with dietary patterns was also assessed.ResultsThree distinctive dietary patterns across all participants were identified from our analyses. Healthy diet, processed diet and mixed diet. Mean food scores indicated statistically significant differences between the dietary patterns for older and younger generations. Older generations showed greater diversity in food items consumed, as well as eating primarily a ‘healthy diet’. The younger generation was more likely to consume a ‘processed diet’. There was significant association between acculturation and deprivation with the distinctive dietary patterns.ConclusionOur investigation highlighted generational differences in consuming a limited range of food items. Identified dietary components may, in part, be explained by specific acculturation modes (assimilation and marginalised) and high socioeconomic deprivation among this particular study population.

scholarly journals Immune and sex-biased gene expression in the threatened Mojave desert tortoise, Gopherus agassizii

PLoS ONE ◽  
2020 ◽  
Vol 15 (8) ◽  
pp. e0238202
Author(s):  
Cindy Xu ◽  
Greer A. Dolby ◽  
K. Kristina Drake ◽  
Todd C. Esque ◽  
Kenro Kusumi
Keyword(s):  
Gene Expression ◽  
Mojave Desert ◽  
Gopherus Agassizii ◽  
Desert Tortoise ◽  
Mojave Desert Tortoise

scholarly journals Mojave desert tortoise (Gopherus agassizii) thermal ecology and reproductive success along a rainfall cline

2015 ◽  
Vol 10 (3) ◽  
pp. 282-294 ◽  
Author(s):  
Annette E. SIEG ◽  
Megan M. GAMBONE ◽  
Bryan P. WALLACE ◽  
Susana CLUSELLA-TRULLAS ◽  
James R. SPOTILA ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Mojave Desert ◽  
Thermal Ecology ◽  
Gopherus Agassizii ◽  
Desert Tortoise ◽  
Mojave Desert Tortoise
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